Nurmi P., Valtonen M.J. & Zheng J.Q. (2001). “Periodic variation of Oort Cloud flux and cometary impacts on the Earth and Jupiter”. Monthly Notices of the Royal Astronomical Society. 327 (4): 1367–1376. Bibcode:2001MNRAS.327.1367N. doi:10.1046/j.1365-8711.2001.04854.x.
Piatek S. & Pryor C. (1993). “Can Galactic Tides Inflate the Apparent M/L's of Dwarf Galaxies?”. Bulletin of the American Astronomical Society. 25: 1383. Bibcode:1993AAS...183.5701P.
Nurmi P., Valtonen M.J. & Zheng J.Q. (2001). “Periodic variation of Oort Cloud flux and cometary impacts on the Earth and Jupiter”. Monthly Notices of the Royal Astronomical Society. 327 (4): 1367–1376. Bibcode:2001MNRAS.327.1367N. doi:10.1046/j.1365-8711.2001.04854.x.